* adds description of paging using sender timestamp
* updates rfc, brings back receiver timestamp
* brings back the receiver timestamp
* renames sender timestamp
* adds discussion about the use of robust timestamp and different usecases of receiver and sender time
* link to open timestamp
* adjusts spacing
* sembr
* minor
* rewording and rephrasing
* formatting
* formatting
* applies comments
* explains attack by an example
* fixes a wrong ts value
* aligns paragraphs